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NAME

lance - LANCE Ethernet device

SYNOPSIS

bind -a #l /net

/net/ether/clone /net/ether/[0-7] /net/ether/[0-7]/data /net/ether/[0-7]/ctl /net/ether/[0-7]/stats /net/ether/[0-7]/type

DESCRIPTION

The LANCE Ethernet interface is a directory containing 9 stream directories: one for each of 8 Ethernet packet types and a clone file.

Each stream directory contains files to control the stream, receive and send data, and supply statistics. Incoming Ethernet packets are demultiplexed by packet type and passed up the corresponding open stream. Reading from the data file reads packets at the head of the stream. A read will terminate at packet boundaries. Each write to the data file causes a packet to be sent. The Ethernet address of the interface is inserted into the packet header as the source address.

A stream is assigned a packet type by opening its ctl file and writing connect n where n is a decimal integer constant identifying the Ethernet packet type. A value of -1 stands for all types. If multiple streams are assigned to a given packet type a copy of the packet is passed up each stream.

Reading the type file returns the decimal value of the assigned Ethernet packet type. Reading the stats file returns status information and the Ethernet address of the interface.

An interface normally receives only packets whose destination address is that of the interface or is the broadcast address, ff:ff:ff:ff:ff:ff. The interface can be made to receive all packets on the network by writing the string promiscuous to the ctl file. The interface remains promiscuous until the control file is closed. The extra packets are passed up only streams of type -1.

SOURCE

/sys/src/9/port/devlance.c

Copyright © 1995 Lucent Technologies. All rights reserved.